Why is the fixing point of the front wing of a F1 car so small?

Why can't the front wing of a Formula 1 car be properly attached to a car, but it's only attached by a small area in the front of the car?

There is no regulation limiting the attachment of the front wing of the car. It's attached in this manner, because it gives an aerodynamic advantage. It's fixed just strong enough so that it won't detach at full speed, but it's not meant to be a bumper to use for crashing to other cars.